#!/usr/bin/perl
sub inramanhinh{
	my $hiddenvar = "This is a hidden variable\n";#bien' an?
	print $hiddenvar;
	print @_,"\n";#@_ la` mang? luu tru~ cac' tham so' truyen` vao`
	print "Tong cua? 2 toan' hang. la` :",($_[0] + $_[1],"\n");#tra? lai. tong? cua? 2 tham so' truyen` vao`
	$_[0];#phan tu return hoac. dung` "return $_[0]" cung~ duoc.
}
$myvar = inramanhinh(10,15);
print $myvar;